What to do
The method
- 01
Prepare the dish.
Heat the oven to 375°F. Lightly butter or grease a 9-by-13-inch baking dish.
- 02
Cook the potatoes.
Cover the potatoes with well-salted water. Boil until fork-tender, about 12–15 minutes. Drain thoroughly and let excess steam escape for several minutes.
- 03
Build the base.
Combine the sour cream, softened butter, cream cheese, milk, Dijon, salt, pepper, garlic powder, and smoked paprika in a large bowl.
- 04
Fold it together.
Add the potatoes, about 2 cups cheddar, most of the bacon, and most of the green onions. Fold gently, breaking some potatoes while leaving plenty of chunks intact.
- 05
Top the casserole.
Spread into the dish and add the remaining cheddar and bacon. Mix the panko, melted butter, and Parmesan, if using, and sprinkle evenly over the top.
- 06
Bake and rest.
Set the dish on a sheet pan and bake uncovered for 35–40 minutes, until bubbling and golden. Rest 10–15 minutes and finish with the reserved onions or chives.
What I learned
Dijon quietly fixes almost everything.
Not enough to make the casserole taste like mustard—just enough to sharpen the cheese, bacon, and potatoes. Despite what modern food culture suggests, there really is a point where adding more cheese stops solving the problem.